@article {1625, title = {Anti-leukemic activity of dasatinib in both p53(wild-type) and p53(mutated) B malignant cells.}, journal = {Invest New Drugs}, volume = {30}, year = {2012}, month = {2012 Feb}, pages = {417-22}, abstract = {

The multi-kinase inhibitor dasatinib induced a variable but significant decrease of viability in both p53(wild-type) (EHEB, JVM-2, JVM-3) and p53(mutated) (MEC-1, MEC-2, BJAB) prolymphocytic B leukemic cells, due to a combination of cell cycle block in G1 and apoptosis. Antibody phospho-kinase array analysis revealed that dasatinib inhibited the phosphorylation of various kinases, including ERK1/2 and p38/MAPK as well as of STAT3 transcription factors, in both p53(wild-type) and p53(mutated) cells. Therefore, dasatinib might offer a novel therapeutic strategy not only for p53(wild-type), but also for p53(mutated) B malignancies that have the worst prognosis and urgently need innovative therapeutic approaches.

}, keywords = {Antineoplastic Agents, Apoptosis, B-Lymphocytes, Cell Line, Tumor, Cell Survival, G1 Phase Cell Cycle Checkpoints, Granulocyte Precursor Cells, Humans, Leukemia, Prolymphocytic, B-Cell, Mitogen-Activated Protein Kinase 1, Mitogen-Activated Protein Kinase 3, Mutation, p38 Mitogen-Activated Protein Kinases, Phosphorylation, Protein Kinase Inhibitors, Pyrimidines, STAT3 Transcription Factor, Thiazoles, Time Factors, Tumor Suppressor Protein p53}, issn = {1573-0646}, doi = {10.1007/s10637-010-9564-6}, author = {Bosco, Raffaella and Rabusin, Marco and Voltan, Rebecca and Celeghini, Claudio and Corallini, Federica and Capitani, Silvano and Secchiero, Paola} } @article {1739, title = {Dasatinib plus Nutlin-3 shows synergistic antileukemic activity in both p53 wild-type and p53 mutated B chronic lymphocytic leukemias by inhibiting the Akt pathway.}, journal = {Clin Cancer Res}, volume = {17}, year = {2011}, month = {2011 Feb 15}, pages = {762-70}, abstract = {

PURPOSE: To analyze the effect of the combination of Dasatinib, a multikinase inhibitor, plus Nutlin-3, a nongenotoxic activator of the p53 pathway, in primary B chronic lymphocytic leukemia (B-CLL) patient samples and B leukemic cell line models.

EXPERIMENTAL DESIGN: The induction of cytotoxicity was evaluated in both primary B-CLL cell samples (n = 20) and in p53(wild-type) (EHEB, JVM-2) and p53(deleted/mutated) (MEC-2, BJAB) B leukemic cell lines. The role of Akt in modulating leukemic cell survival/apoptosis in response to Dasatinib or Dasatinib + Nutlin-3 was documented by functional experiments carried out using specific pharmacological inhibitors and by overexpression of membrane-targeted constitutively active form of Akt.

RESULTS: The combination of Dasatinib + Nutlin-3 exhibited a synergistic cytotoxicity in the majority (19 out of 20) of B-CLL samples, including patients carrying 17p- (n = 4), and in both p53(wild-type) and p53(deleted/mutated) B leukemic cell lines. At the molecular level, Dasatinib significantly counteracted the Nutlin-3-mediated induction of the p53 transcriptional targets MDM2 and p21 observed in p53(wild-type) leukemic cells. Conversely, Nutlin-3 did not interfere with the ability of Dasatinib to decrease the phosphorylation levels of ERK1/2, p38/MAPK, and Akt in both p53(wild-type) and p53(deleted/mutated) B leukemic cell lines. A critical role of Akt downregulation in mediating the antileukemic activity of Dasatinib and Dasatinib + Nutlin-3 was demonstrated in experiments carried out by specifically modulating the Akt pathway.

CONCLUSIONS: These findings suggest that Dasatinib + Nutlin-3 might represent an innovative therapeutic combination for both p53(wild-type) and p53(deleted/mutated) B-CLL.

}, keywords = {Antineoplastic Agents, Apoptosis, Cell Line, Tumor, Cell Survival, Down-Regulation, Drug Synergism, Humans, Imidazoles, Leukemia, Lymphocytic, Chronic, B-Cell, Mutation, Piperazines, Protein Kinase Inhibitors, Protein Kinases, Proto-Oncogene Proteins c-akt, Pyrimidines, Thiazoles, Transcription, Genetic, Tumor Suppressor Protein p53}, issn = {1078-0432}, doi = {10.1158/1078-0432.CCR-10-2572}, author = {Zauli, Giorgio and Voltan, Rebecca and Bosco, Raffaella and Melloni, Elisabetta and Marmiroli, Sandra and Rigolin, Gian Matteo and Cuneo, Antonio and Secchiero, Paola} } @article {1729, title = {miR-34a induces the downregulation of both E2F1 and B-Myb oncogenes in leukemic cells.}, journal = {Clin Cancer Res}, volume = {17}, year = {2011}, month = {2011 May 1}, pages = {2712-24}, abstract = {

PURPOSE: To elucidate new molecular mechanisms able to downregulate the mRNA levels of key oncogenes, such as B-Myb and E2F1, in a therapeutic perspective.

EXPERIMENTAL DESIGN: B-Myb and E2F1 mRNA levels were evaluated in primary B chronic lymphocytic leukemia (B-CLL, n = 10) and acute myeloid leukemia (AML, n = 5) patient cells, in a variety of p53(wild-type) and p53(mutated/deleted) leukemic cell lines, as well as in primary endothelial cells and fibroblasts. Knockdown experiments with siRNA for p53 and E2F1 and overexpression experiments with miR34a were conducted to elucidate the role of these pathways in promoting B-Myb downregulation.

RESULTS: In vitro exposure to Nutlin-3, a nongenotoxic activator of p53, variably downregulated the expression of B-Myb in primary leukemic cells and in p53(wild-type) myeloid (OCI, MOLM) and lymphoblastoid (SKW6.4, EHEB) but not in p53(mutated) (NB4, BJAB, MAVER) or p53(deleted) (HL-60) leukemic cell lines. The transcriptional repression of B-Myb was also observed in primary normal endothelial cells and fibroblasts. B-Myb downregulation played a critical role in the cell-cycle block in G(1) phase induced by Nutlin-3, as shown by transfection experiments with specific siRNA. Moreover, we have provided experimental evidence suggesting that miR-34a is a central mediator in the repression of B-Myb both directly and through E2F1.

CONCLUSIONS: Owing to the role of B-Myb and E2F1 transcription factors in controlling cell-cycle progression of leukemic cells, the downregulation of these oncogenes by miR-34a suggests the usefulness of therapeutic approaches aimed to modulate the levels of miR-34a.

}, keywords = {Base Sequence, Cell Cycle Proteins, Cell Line, Tumor, Cells, Cultured, Down-Regulation, E2F1 Transcription Factor, Gene Expression Regulation, Leukemic, HCT116 Cells, HL-60 Cells, Humans, Imidazoles, Leukemia, MicroRNAs, Models, Biological, Oncogenes, Piperazines, Sequence Homology, Nucleic Acid, Trans-Activators, Transfection}, issn = {1078-0432}, doi = {10.1158/1078-0432.CCR-10-3244}, author = {Zauli, Giorgio and Voltan, Rebecca and di Iasio, Maria Grazia and Bosco, Raffaella and Melloni, Elisabetta and Sana, Maria Elena and Secchiero, Paola} } @article {1758, title = {Molecular targets for selective killing of TRAIL-resistant leukemic cells.}, journal = {Expert Opin Ther Targets}, volume = {15}, year = {2011}, month = {2011 Aug}, pages = {931-42}, abstract = {

INTRODUCTION: TNF-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family of cytokines, and shows promising therapeutic activity against solid tumors and lymphomas, in a variety of Phase I and II clinical trials. In contrast, primary leukemias have shown poor susceptibility to TRAIL-mediated cytotoxicity, suggesting the need for sensitizing TRAIL-resistant leukemic cells, by combining soluble recombinant TRAIL either with chemotherapeutic drugs, or with targeted small molecules.

AREAS COVERED: This review discusses potential therapeutic applications of combinations able to restore the sensitivity of leukemic cells to either recombinant TRAIL or anti-TRAIL-receptor agonistic antibodies for the treatment of hematological malignancies.

EXPERT OPINION: Up-to-date knowledge of the most innovative anti-leukemic therapies including functional screening of specific-sensitizers, enhancing TRAIL-mediated cytotoxicity. Strategies aimed to enhance TRAIL-mediated apoptosis, include the combination of novel sensitizers, functionally identified from libraries of pharmaceutically active, synthetic or naturally derived compounds. Other approaches aim to employ the administration of stem cells engineered to express TRAIL, in the leukemic stem cell niche, and promise to be a successful treatment with reduced specific toxicity.

}, keywords = {Humans, Leukemia, TNF-Related Apoptosis-Inducing Ligand}, issn = {1744-7631}, doi = {10.1517/14728222.2011.580278}, author = {Zauli, Giorgio and Bosco, Raffaella and Secchiero, Paola} } @article {1726, title = {Recent advances in the therapeutic perspectives of Nutlin-3.}, journal = {Curr Pharm Des}, volume = {17}, year = {2011}, month = {2011}, pages = {569-77}, abstract = {

Nutlin-3 is a small molecule inhibitor of the MDM2/p53 interaction, which leads to the non-genotoxic p53 stabilization, activation of cell cycle arrest and apoptosis pathways. A series of recent studies have strengthened the concept that selective, non-genotoxic p53 activation by Nutlin-3 might represent an alternative to the current cytotoxic chemotherapy, in particular for pediatric tumors and for hematological malignancies, which retain a high percentage of p53(wild-type) status at diagnosis. Like most other drugs employed in cancer therapy, it will be unlikely that Nutlin-3 will be used as a monotherapy. In this respect, Nutlin-3 shows a synergistic cytotoxic effect when used in combination with innovative drugs, such as TRAIL or bortozemib. Although Nutlin-3 is currently in phase I clinical trial for the treatment of retinoblastoma, its effects on normal tissues and cell types remain largely to be determined and will require further investigation in the future years.

}, keywords = {Antineoplastic Agents, Antineoplastic Combined Chemotherapy Protocols, Drug Synergism, Genes, p53, Humans, Imidazoles, Neoplasms, Piperazines, Proto-Oncogene Proteins c-mdm2, Tumor Suppressor Protein p53}, issn = {1873-4286}, author = {Secchiero, Paola and Bosco, Raffaella and Celeghini, Claudio and Zauli, Giorgio} }